Initial research by our group has demonstrated that children in the 3rd and 4th grades in Butte, Montana (Silver Bow County) excrete mutagenic substance(s) in urine samples taken during the school day. Mutagens have also been extracted from air filter samples taken in the area at the same time. The population of Silver Bow County has been shown to be at higher risk of dying of lung cancer than the national average in a state of lower than normal mortality and the town of Butte contains over 90% of the population of that county. This investigation will determine the number of children excreting mutagen(s) in Butte by using rapid mutagen assays of column concentrates, especially the Ames Salmonella assay, E. coli repair assay, Saccharomyces mutation and gene conversion assays. Selected positive and negative urine samples will also be assayed by CHO cell sister chromatid exchange and unscheduled DNA synthesis as well as mammalian cell forward mutation assay. Data will also be obtaned on the relative sensitivities and efficacies of the short term assays and on necessary statistical parameters of testing. Any mutagenic metabolites excreted by children will then be collected, pooled, isolated and characterized using thin layer chromatography, solvent extraction procedures and any other necessary isolation techniques and microbial tests. Air filter samples and water samples from the area where the children live will be assayed by the same techniques and the isolated mutagenic components will be compared chemically with those from urine samples. If no correspondence is found dietary sources of mutagens will be investigated through both chemical analysis and interview data. We will identify the source(s) of mutagens with the purpose of being able to limit exposure of these children and to make their families aware of the possible risks. In this analysis synergism and antagonism in mixtures is amenable to investigation since fractions from urine samples and filter extracts will be available for mixing.